Access plug



J. P. GOULD ACCESS PLUG Dec. '23, 1958 4@ IN VEN TOR. Lgyj? EV: W hllh f/1R l W w i I m i m L f m V r QV y@ @L f@ ww/ w aan ACCESS PLUG Jay P. Gould, Glendale, Calif.

Appncaaon May 2s, 1956, serial No. ssaatz 11 claims. (ci. 22o- 39) i This invention relates to pressure containers and more specifically to an access plug for such containers.

It has long been a problem to gain access to the interior of pressure containers for high pressure fluids' such as oil well casing heads, fluid pipe lines and the like, without disruption of the pressure or of fluid flow in the container, if flow is in progress. To overcome the problem I have developed an adapter comprising a'plug and nipple described and claimed in my copending application Serial No. 160,222 filed May 5, 1950, now Patent No. 2,804,279. That device effectively renders the interior of pressure containers accessible for such purposes as testing, sampling and the like, and when a special pressure confining tool, such as described and claimed in my application Serial No.'247,005 filed September l7, 1951, now Patent No. 2,744,310 issued May 8, 1956, is applied thereto, the plug may be removed and replaced while the fluid therein is under pressure and even when flow exists therein, without disruption of either pressure or flow.

Briefly stated, the plug above referred to, affords access to the interior of the container through an internally threaded nipple, or other appropriate portion of the container. Normally, the nipple or portion of the con- `tainer is closed by the externally threaded access plug,

and access is gained by removing the plug, -with the pressure confining tool, above referred to, in the manner described in the above applications. The diameter of the plug determines the degree of access that is afforded and, necessarily limits the size of any device that may be introduced into the container. For smaller openings in the container the above described plugs are entirely adequate, but in the event that the pressure difference between the interior'and the exterior of the container is relatively large and a relatively large opening into the interior of the container is required, difficulty will be encountered in initially turning a plug of such size to effect its removal.

It. is therefore a primary object of this invention to provide an access plug for pressure containers for high pressure fluid, which may be o-f relatively large diameter and yet which is easily removed from the container.

Another object is to provide an access plug for pressure containers for high pressure fluid that will by-pass fluid from one to the other end thereof for balancing the forces thereon and thus reduce the effort required to remove the plug.

Other objects and advantages of' the invention will become .apparent from the subsequent description taken in conjunction-with the appended drawing wherein:

`Fig. 1 is a fragmentary sectional View on a reduced scale of an installation pro-vided with one embodiment of the plug mounted in a pressure container or nipple and illustrating the relative locations of accessory elements used for installation and removal of the plug.

Fig. 2 is a sectional view of the plug illustrating the relative positions of its element when in plugging relation.

Fig. 3 is a view similar to Fig. 2 illustrating the relative position of its elements during removal of the plug, and

Fig. 4 is an end View of the plug taken along line 4-4 of Fig. 3.

In general, the objects of the invention are accomplished by providing an access plug that may be threadedly inserted and sealed in an opening in a pressure container for high pressure fluid, but which has means that is shiftable therein to open a passage through the plug. Upon being opened, the passage by-passes fluid from one end of the plug to its opposite end, if a pressure differential exists there-between. By properly confining any bypassed fluid with an appropriate tool, as described hereinafter, the forces exerted by the fluid on the opposite ends of the plug are balanced, and the plug may be unscrewed and removed without additional eflort being required to overcome the huge resisting resultant force caused by the pressure differential that would otherwise exist.

Referring to the drawing, Fig. 1 shows one embodiment of the plug, indicated generally at 11, installed in an internally threaded portion of a pressure container 12., such as a nipple attached to a pipe line, an oil well casing head o-r any other container for high pressure fluid. The function of the instant plug 11 is in principal the same as the plug described in my aforementioned application Serial No. 160,222. It is installed and removed from the container in substantially the same manner, and it requires the same accessories for installaalso be capable of cooperation with the container to form passage 19 of the tool.` lt must also be sealed so as to retain any fluid coming from the container, and must have a suitable plug grasping and manipulating head that may extend from, and be withdrawn into, passage 19, such as head 21. In general, the plug 11 is installed by first loading it into tool 14. Thereafter tool 14 is attached to the valve 13 which had been previously attached to container 12. Valve 13 is then opened, the plug 11 is inserted through passage 16 and screwed into the container 12. When the plug is so installed, tool 14 and valve 13 may be removed. In general, removal of the plug 11 from container 12 is accomplished by a reversal of the aforesaid steps. The procedures just described are in common with those used to effect installation and removal of the plug .described in the aforementioned application Serial No. 160,222. A more detailed description of the removal of the instant plug will be described hereinafter.

As previously indicated the instant plug is adapted for use in situations involving a high pressure differential where relatively large diameter plugs are required. As shown in Figs. 2 and 3, this embodiment comprises a tubular outer plug member 22 adapted to be screwed into the threaded portion of the container y12, and an inner -plug'member 23 disposed within the outer plug member 22 and cooperable therewith to provide a lluid by-passing passage through the plug.

To receive the plug 11, container 12 is -internally threaded, as at 2li, andouter plug member 22'is externally threaded to cooperate with the threaded Vportion Although any type -threads may serve,'it is preferable that machine threads be used, since it is contemplated that the plug 11 may be repeatedly removed and reinserte in yportion 12. Since machine threads are not self sealing, independent sealing means is required to seal the junction between outer plug member 22 and container 1,2. To that end, a sealing ring 26 such as an 5S ring is provided, and in the instant embodiment, vit is mounted in a groove in the surface of outer plug member 2?. and located inwardly from the threaded portions ,2li so that uid is sealed therefrom to prevent fouling the threads thereby. In addition, the outer plug member 22 is ternally tapered adjacent its inner end, as at 27, to cooperate with a corresponding taper 2S in the portion 12. When plug 11 is properly seated in container 12, their tapered portions 27 and 28 engage and prevent undue insertion of plug 11. The outer plug 22 may of course be made straight at its lower end if desired.

As shown in Figs. 2, 3 and 4, the inner plug vmember 23 is, in the preferred embodiment, generally cylindrical and is disposed withinthe axial inner bore of the outer plug member 22. The inner plug member 23 is also movable axially relative to the outer plug member to open and close a passage through the plug.

To this end, outer plug member 22 is internally threaded, as at 29, to cooperate with external threads 3,1 on inner plug member 23. Again, preferably, these are machine threads, and the juncture between members 22 and 23 is sealed against fluid by a seal such as an O ring 32, positioned in this instance on the inner plug menu ber 23 to cooperate with the inner wall of outer plug member 22 inwardly of the threads 31. In addition, threads 31 are of the same hand as threads 24. Rotation of the inner plug member 23 may be eiected by any appropriate tool, and to provide means for engagement with such tool the inner plug is provided with a hexagonal head 33 positioned on its outer end.

' To provide a passage for iluid through the plug, and for other purposes hereinafter described, inner plug member 23 has an axial bore 34 extending from its outer end through head 33 to a point inwardly of the sealing ring 32. At its inner end it is provided with at least one port or passage 36. In the instant case four such ports 36 are shown.

r[he plug members 22 and 23 cooperate to open and close the passage through plug 11, upon movement of inner plug member 23 between an open position and a closed position relative to outer plug member 22. Fig.

2 illustrates the plug 11 as it appears when inner plug member is in closed position and Fig. 3 illustrates the plug 11 as it appears when inner plug member is in fully opened position. Inner plug member 23 is externally tapered from the ports 36, as at 37, to cooperate with the inner wall of plug member 22 which is provided with a tapered seat 3S. The tapered end 37 of plug 23 has a packing ring 39 positioned against a shoulder thereon to engage the seat 3S, of outer plug member 22 to provide a seal therebetween, closing ports 36, when the inner plug member is in closed position. inner plug member 23 is moved to open position by being rotated to axially shift it outwardly. By virtue of the tapered character of the members 22 and 23, the outward shifting of inner plug member 23 relative to outer plug member 22, creates a space or passagedl, shown in Fig. 3, that interconnects ports 36 and the interior of container l2, and thus establishes lflow communication therethrough to by-pass the liuid under pressurethrough the plug. -The packing ring 39 is held in position on inner plug member 23 by a packing nut 43 onV a threaded projection 44.

72,835,530 j. Y- y n The pressure on opposite ends of the plug is thus equalized. The cooperating threads at 24 thus are relieved of pressure and the resistance due to friction therebetween is thereby reduced. The outer plug member 22 can therefore be readily rotated to remove it.

To elect the removal of plug 11, rotation of outer plug member 22 can be accomplished in several ways. However, in the instant embodiment, such rotation is eifeeted through continue-d yrotation of the inner plug member 23 after it has been shifted to open position. This is accomplished by providing shoulder means that frictionally engages outer plug member 22 when the inner plug member 23 is in the fully open position. ln the embodiment illustrated that shoulder means comprises a hexagonal uut 46 dimensioned across its ats to be at least equal to the diameter of the axial bore at the inner end of outer plug member 22. Nut 46 has a neck portion 4S that projects into the bore of the inner end of outer plug member 22 and abuts against packing nut 43. Nut 46, like packing nut 443, is screwed onthe threaded projection 44, and in order that nut 46 will not loosen upon rotation of inner plug member 23, the threads of projection 44 are of opposite hand to threads 31. Upon shifting of the inner plug member 23 to the fully open position, nut i6 frictionally engages the inner end of outer plug member 22, preventing further shitting of the inner plug member 23 relative to the outer plug member 22. Any further rotation of inner plug member 23 will, through nut 46, cause the outer plug member 22 to vrotate and in as much as the threads 31 and the threads 24 are of the same hand, such further rotation will withdraw the entire plug 11 from the container 12. VIn order to prevent nut 46 from closing the passage through the plug, a pluralityvof radial slots 47, extending under the nut 46 to the passage, are provided in the end of outer plug member 22.'`

It is contemplated that the tool 14, described fully in my application Serial No. 247,005 and fragmentarily shown herein, will be used to install and remove the plug. As previously stated, tool 14 is a pressure contining'tool, and, as illustrated in the drawing, has an extendable barrel portion 49 that includes head 21 providedwith a socket portion 51 adapted to engage the hexagonal head 33. From the center of the socket projects a pilot element 52. The pilot element 52 is adapted to be inserted in bore 34 for centering the tool over the plug. A pair of spring actuated detents 53are carried by the pilot element 52 and lare adapted to engage behind a shoulder 54, formed in bore 34, as shown in Fig. 3. Such engagement is utilized only after the plug 11 has been screwed out of portion 12 and threads 24 are no longer in engagement so that the plug can be withdrawn through the valve 13 into the body of the tool 14.

To elect the removal of plug 11 from the container 12, valve 13 is connected to container 12 over the plug as shown, and tool 14 is, in turn, connected to the valve. Since tool 14 is properly sealed to conne any lluid conducted to it from the plug, valve 13 may be opened, and the barrel portion 49 of tool 14- may be projected through the valve so that socket portion 51 may be seated on head 33. Tool 14 is then manipulated to rotate plug 11 to effect its removal. In as much as the inner plug member 23 is substantially smaller in diameter than is outer plug member 22, it will commence to rotate rst. Rotation of the inner plug member 23 to move it axially outwardly relative to the outer plug member 22 opens the passage through the plug. Upon opening of the passage, uid is by-passed through the plug into the valve 13 and tool 14. The by-passed fluid, confined by the valve 13 and tool 14, quickly equalizes the pressure upon the opposite ends of plug 11. Rotation of the inner plugmember 23 moves the nut 46 into engagement with the lower end of outer plug member 22 and, in as much as the pressure is in balance on opposite sides of the plug, a relatively small turning force assenso the container 12. Upon disengagement of the threads 24, plug 11 is withdrawn through the valve 13 into the barrel of tool 14. The valve 13 is then closed, pressure is relieved in the tool 14, and the tool 14 disconnected from the valve 13. The plug 11 may then be removed from the tool.

From the foregoing it is seen that this invention provides a novel access plug for pressure containers for high pressure duid that will by pass pressure from one end to the other thereof before withdrawal thereof has commenced. The by-passed iluid, confined in an appropriate tool, balances the forces on opposite ends of the plug and thus reduces the turning eiort necessary to effect removal of the plug. Thus, a plug incorporating the features of the invention can be of relatively large diameter without requiring excessive eiort to remove it.

Although the invention has been described in connection with a certain specific structural embodiment of the invention, it is to -be understood that various modiiications and alternative structures may be resorted to witho-nt departing from the scope of the invention as dened in the appended claims.

I claim:

l. An access plug for use in an internally threaded portion of a pressure container for high pressure iluid, said plug comprising an outer plug member externally threaded for engagement with said threaded portion of the container, and an inner plug member mounted in said outer plug member and shiftable relative thereto, shifting of said inner plug member in one direction opening a passage through said outer plug member to bypass pressure fluid from the inner end to the outer end of said plug, said inner plug member having means engageable with the outer plug member for effecting rotation thereof when the inner member is shifted after said passage is opened, whereby said plug may be disengaged from the container when under pressure.

2. An access plug for use in an internally threaded portion of a pressure container for high pressure lluid, said plug comprising an outer plug member externally threaded for engagement with said threaded portion of the container, and an inner plug member extending into said outer plug member and rotatable in one direction relative to said outer plug member to open a passage through said outer plug member to by-pass pressure uid from the inner end to the outer end of said plug, said inner plug member having means engageable with the outer plug member, after said passage is open for effecting rotation of said outer plug member upon continued rotation of said inner plug member, whereby said plug may be disengaged from the container when under pressure.

3. An access 'plug for use in an internally threaded portion of a pressure container for high pressure uid, said plug comprising an outer plug member externally threaded for engagement with said threaded portion of the container, and a generally cylindrical inner plug member extending into said outer plug member and axially shiftable in one direction therein and thereby opening a passage through said outer plug member to llay-pass pressure fluid from the inner end to the outer end of said plug, said inner plug member having means engageable with the outer plug member for effecting rotation of said outer plug member when the inner plug member is shifted in said one direction after said passage is open, whereby said plug may be disengaged from the container when under pressure.

4. An access plug according to claim 1 and further characterized in that said outer plug member is externally threaded adjacent its outer end and is provided with pressure sealing means positioned inwardly from said threads for sealing the juncture between said outer plug member and the container, whereby to prevent fouling of said threads by the pressure iluid.

5. An access plug for use in an internally threaded 'portion of a pressure .container for high pressure Itluid,

6 said Vplug comprising a tubular outer plug member ex ternally threaded for engagement with said threaded portion of the container and `having an internally threaded portion, and a generally cylindrical inner plug member extending axially into said outer plug member and having threads engaging said internally threaded portion for axially shifting said inner plug member relative to said outer plug member between a closed and an open position upon rotation of said inner plug member, said plug members having cooperating portions that move apart and open a passage through said plug for by-passing iluid from the inner end to the outer end of said plug when said inner plug member is shifted to said open position and that move together and seal said passage when said inner plug member is shifted to said closed position, said inner plug member having means engageable with the outer plug member for effecting rotation thereof upon continued rotation of said inner plug member after its having been shifted to open position, whereby said plug -may be disengaged from the container when under pressure.

tion of a pressure container for high pressure fluid, said plug comprising an outer plug member externally v threaded for engagement with said threaded portion of the container and having an axial bore therethrough tapered yadjacent the inner end of said outer plug mem er and internal threads therein adjacent the outer end of said outer plug member, and an inner plug member extending through said bore and having threads engaging said internal threads for axially shifting said inner plug member relative to said outer plug member by rotation of said inner plug member, said inner plug member having a passage opening radially at a point inwardly of said threads and having a tapered portion located inwardly of said point and cooperating with the taper in said outer plug member for closing said passage when said inner plug member is shifted inwardly and to open said passage when said inner plug member is shifted outwardly, said inner plug member also having means engageable wi'h said outer plug member for eifecting rotation thereof upc-n continued rotation of said inner plug member after its having been shifted to open said passage, whereby said plug may be disengaged from the container under pressure.

7. An access plug according to claim 6' and further characterized in that said inner plug is pro-vided with a circumferential pressure sealing ring positioned between its threads and its tapered portion to prevent `fouling of said threads and is also provided with circumf=rential packing positioned yin said tapered portion of said inner plug member to cooperate with the taper in said'outer plug member when the inner plug member is in closed position to seal the juncture therebetween.

8. An access plug for use in an internally threaded portion of a pressure container for high pressure fluid, said plug comprising an outer plug member having external threads for engagement with said threaded portion of the container and having a bore therethrough with internal threads therein adjacent the outer end of said outer plug member, and a generally cylindrical inner plug member extending axially into said bore and having threads engaging said internal threads for axially shifting said inner plug member relative to said outer plug member, the shifting of said inner plug member in one direction opening a passage through said plug to by-pass pressure Huid from the inner end to the outer end of said plug, said passage comprising in part the bore in said outer plug member, said inner plug member alsoA having shoulder means on one end thereof engageable with said outer plug member for effecting rotation of said outer plug member upon continued rotation of said inner plug member after said passage has been opened, whereby said plug may be disengaged from the container under pressure.

9. An access plug according to claim .S and furthe):

7` characterized-.inthat said internal threadsl in saidouterrY plug memberare of thesame bandas the external-threads thereon.

10. An access plug for usein-an internally threaded portionof a pressure container for high'pressure fluid, saidplugacomprisingan outer plug member-*having external threads-for engagement with said threaded portion. of. the container and havinga bore therethroughk with internal threads therein of the'sarne hand-as said' externalthreads and positioned adjacent the outer end ofY said unter` plug` member, andral generally cylindrical inner. plug member extending axially int-o said bore thro-ughA said-*outer plug member and having threads engaging saidinternal threads for axially shifting said inner plugwrnemberrelative to'saidouter plugs member, axial shifting of .SaidiHner plugrvmember outwardly relative to said Vouterhplug-memberlopening a passage through said plug to by-pass pressurerliuid from the inner tothe outer endtcf said plug, said passage comprising in part the b-ore insaidouter4 plug member,v said inner plug-havinga proaff jectiononsits inner-endtand a nut threaded thereon and yadapted tovffrictionally'engage-,the inner end of said outer plug' membertoreleet rotation of said outer plug member upon'continuecl` rotation of said inner plug member after v its having been-shiftedto kopenv saidvpassage, the threads of said nut being of the opposite hand of said external threads, wherebyy said- `plug may. be disengaged from the container under pressure.

1,1. Anaccess plug` according to vclaim l() and further characterized in thatthe inner end of said outer plug member isl slottedto provide a communicating channel under said nut to said passage upon engagement of said nut with-said end.

RferencesCited in the le of this patent UNITED STATES PATENTS 2,425.3.133 Hammerstein Aug. 12, 1947 2,7.12 ,829 Whitaker July l2, 1955 20` 2,769,566k Thompson Nov. 6, 1956 

